/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.socket.config.annotation;

import org.springframework.beans.factory.config.CustomScopeConfigurer;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.lang.Nullable;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.messaging.simp.SimpSessionScope;
import org.springframework.messaging.simp.annotation.support.SimpAnnotationMethodMessageHandler;
import org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler;
import org.springframework.messaging.simp.config.AbstractMessageBrokerConfiguration;
import org.springframework.messaging.simp.stomp.StompBrokerRelayMessageHandler;
import org.springframework.messaging.simp.user.SimpUserRegistry;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.config.WebSocketMessageBrokerStats;
import org.springframework.web.socket.handler.WebSocketHandlerDecoratorFactory;
import org.springframework.web.socket.messaging.DefaultSimpUserRegistry;
import org.springframework.web.socket.messaging.SubProtocolWebSocketHandler;
import org.springframework.web.socket.messaging.WebSocketAnnotationMethodMessageHandler;

/**
 * Extends {@link AbstractMessageBrokerConfiguration} and adds configuration for
 * receiving and responding to STOMP messages from WebSocket clients.
 *
 * <p>Typically used in conjunction with
 * {@link EnableWebSocketMessageBroker @EnableWebSocketMessageBroker} but can
 * also be extended directly.
 *
 * @author Rossen Stoyanchev
 * @author Artem Bilan
 * @since 4.0
 */
public abstract class WebSocketMessageBrokerConfigurationSupport extends AbstractMessageBrokerConfiguration {

    @Nullable
    private WebSocketTransportRegistration transportRegistration;


    @Override
    protected SimpAnnotationMethodMessageHandler createAnnotationMethodMessageHandler() {
        return new WebSocketAnnotationMethodMessageHandler(
                clientInboundChannel(), clientOutboundChannel(), brokerMessagingTemplate());
    }

    @Override
    protected SimpUserRegistry createLocalUserRegistry(@Nullable Integer order) {
        DefaultSimpUserRegistry registry = new DefaultSimpUserRegistry();
        if (order != null) {
            registry.setOrder(order);
        }
        return registry;
    }

    @Bean
    public HandlerMapping stompWebSocketHandlerMapping() {
        WebSocketHandler handler = decorateWebSocketHandler(subProtocolWebSocketHandler());
        WebMvcStompEndpointRegistry registry = new WebMvcStompEndpointRegistry(
                handler, getTransportRegistration(), messageBrokerTaskScheduler());
        ApplicationContext applicationContext = getApplicationContext();
        if (applicationContext != null) {
            registry.setApplicationContext(applicationContext);
        }
        registerStompEndpoints(registry);
        return registry.getHandlerMapping();
    }

    @Bean
    public WebSocketHandler subProtocolWebSocketHandler() {
        return new SubProtocolWebSocketHandler(clientInboundChannel(), clientOutboundChannel());
    }

    protected WebSocketHandler decorateWebSocketHandler(WebSocketHandler handler) {
        for (WebSocketHandlerDecoratorFactory factory : getTransportRegistration().getDecoratorFactories()) {
            handler = factory.decorate(handler);
        }
        return handler;
    }

    protected final WebSocketTransportRegistration getTransportRegistration() {
        if (this.transportRegistration == null) {
            this.transportRegistration = new WebSocketTransportRegistration();
            configureWebSocketTransport(this.transportRegistration);
        }
        return this.transportRegistration;
    }

    protected void configureWebSocketTransport(WebSocketTransportRegistration registry) {
    }

    protected abstract void registerStompEndpoints(StompEndpointRegistry registry);

    @Bean
    public static CustomScopeConfigurer webSocketScopeConfigurer() {
        CustomScopeConfigurer configurer = new CustomScopeConfigurer();
        configurer.addScope("websocket", new SimpSessionScope());
        return configurer;
    }

    @Bean
    public WebSocketMessageBrokerStats webSocketMessageBrokerStats() {
        AbstractBrokerMessageHandler relayBean = stompBrokerRelayMessageHandler();

        // Ensure STOMP endpoints are registered
        stompWebSocketHandlerMapping();

        WebSocketMessageBrokerStats stats = new WebSocketMessageBrokerStats();
        stats.setSubProtocolWebSocketHandler((SubProtocolWebSocketHandler) subProtocolWebSocketHandler());
        if (relayBean instanceof StompBrokerRelayMessageHandler) {
            stats.setStompBrokerRelay((StompBrokerRelayMessageHandler) relayBean);
        }
        stats.setInboundChannelExecutor(clientInboundChannelExecutor());
        stats.setOutboundChannelExecutor(clientOutboundChannelExecutor());
        stats.setSockJsTaskScheduler(messageBrokerTaskScheduler());
        return stats;
    }

    @Override
    protected MappingJackson2MessageConverter createJacksonConverter() {
        MappingJackson2MessageConverter messageConverter = super.createJacksonConverter();
        // Use Jackson builder in order to have JSR-310 and Joda-Time modules registered automatically
        Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.json();
        ApplicationContext applicationContext = getApplicationContext();
        if (applicationContext != null) {
            builder.applicationContext(applicationContext);
        }
        messageConverter.setObjectMapper(builder.build());
        return messageConverter;
    }

}
